The present invention relates to a process for preparing halogenated aliphatic, alicyclic or aralkyl hydrocarbyl nitriles, such as 4-chlorobutyronitrile, by reacting a metal or ammonium cyanide with a dihalogenated aliphatic, alicyclic or aralkyl hydrocarbyl compound in the presence of water and a phase transfer catalyst such as a quaternary ammonium or phosphonium salt.
Haloalkyl nitriles have customarily been prepared by reacting dihaloalkanes with a metallic cyanide in a medium capable of solvating both reactants in the same phase. One medium extensively used has been a 50--50 ethanol-water mixture. The ethanol places the dihalide in solution, and the water dissolves the metal cyanide. The use of ethanol in the reaction system requires that precautions be taken during the reaction to avoid the danger of fire. The yield of the desired halohydrocarbyl nitrile prepared by the above method is usually in the range of 55 to 75 percent based upon the dihaloalkane reactant. One of the principal side reactions which reduces the yield of the product is the formation of the dinitrile. If a method for preparing halohydrocarbyl nitriles could be devised which could eliminate the need for an organic solvent while simultaneously improving the yield of the halohydrocarbyl nitrile product, it would represent an important advance in the art. Providing such a process constitutes one of the principal objects of this invention.